---
title: "Free Regular Expression Tester | formformform"
description: "Test JavaScript regular expressions, flags, matches and capture groups in your browser."
url: "https://www.formformform.com/tools/regex-tester"
type: static
generatedAt: "2026-08-23T18:56:58.727Z"
---
# Regex tester

Test regular expressions against sample text with matches and capture groups highlighted.

Pattern (without / /)

Flags

Test text

Replacement (optional)

### Matches

Replacement preview

Test a JavaScript regular expression against sample text. Matches, capture groups, indexes and replacements update as you type, entirely in the browser.

## Native JavaScript rules

Patterns use the same RegExp engine as modern browser code.

## See every match

Global matching lists indexes and captured groups while guarding against zero-length loops.

## Frequently asked questions

Why does a pattern work elsewhere but not here?

Regular-expression syntax differs between languages. This tool uses JavaScript syntax.

Is my test text uploaded?

No. Testing occurs locally.

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## Want the form to collect the answers too?

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[Start free](https://app.formformform.com/register?utm_source=landing&utm_medium=bottom&utm_campaign=tools&utm_content=regex-tester)